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Biomedical subjects

Y Shimada

Publications and source records attributed to Y Shimada.

At least 505 records · Page 28Linked to original sources
PubMed1992

[A case of hepatocellular carcinoma responding to intraarterial infusion of epirubicin and mitomycin C].

A 64-year-old male was admitted for treatment of hepatocellular carcinoma. He was diagnosed as having many tumors in the area of S6 and the AFP level was elevated to 878 ng/ml. Initially, intraarterial infusion of Epirubicin only was not effective. After the first course of treatment, tumors increased in size and the AFP level was elevated. Next, intraarterial infusion of Epirubicin and Mitomycin C was performed. After the second course of treatment, the AFP level decreased from 5,006 ng/ml to 754 ng/ml and the tumors had almost completely disappeared on angiography. The tumors continued to decrease in size and thereafter the AFP level decreased to 10 ng/ml and was not elevated. The tumors almost completely disappeared in this case, and the coadministration of Epirubicin and Mitomycin C provided effective.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

[The effects of protease inhibitor upon the ischemia-reperfusion injury].

The purpose of the study is to investigate the effects of protease inhibitor (Nafamostat mesilate: NM) upon myocardial protection. Hearts were subjected to 20 min working control perfusion followed by 3 min cardioplegic infusion with the St. Thomas Cardioplegic Solution (ST) contained various concentrations of NM, and global ischemia for 33 min at 37 degrees C (Exp. 1) or 150 min at 20 degrees C (Exp. 2). Hearts were then converted to Langendorff reperfusion (the leakage of Creatine Kinase (CK) and Cathepsin B (Cat-B) ware measured) and 20 min working reperfusion. Various concentrations of NM added during Langendorff reperfusion (Exp. 3). During working perfusion cardiac functions (aortic flow (AoF), coronary flow (CoF), heart rate (HR), aortic pressure (AoP)) were measured, and expressed as the percent recovery of pre-ischemic control value. Post-ischemic recovery of AoF (%AoF) showed the bell-shaped dose-response curve, and the optimal dose was 3 microM (Exp. 1) and 10 microM (Exp. 2) respectively. There was a significant (p < 0.05) increase of %AoF in optimal dose compared with that in controls (64.2 +/- 1.2% vs 52.3 +/- 2.5% in Exp. 1, 68.9 +/- 3.1% vs 54.1 +/- 1.4% in Exp. 2). These increase of functional recovery reflected in the values for CK and Cat-B leakage. The addition of NM in ST reduced CK and Cat-B leakage significantly in the concentration of 5 microM (in Exp. 1) and 10 microM (in Exp. 2) respectively. But the addition of NM in reperfusate did not reduced CK leakage significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Chemotherapy for advanced pancreatic carcinoma].

In advanced pancreatic cancer, chemotherapy has no curative potential, and the goal is to palliate symptoms or delay their onset so as to improve the quality of life of patients. There is no standard chemotherapeutic regimen with a clear advantage in survival prolongation or response rate, over any other regimen. Moreover, difficulties in determining the chemotherapeutic response have made accurate determination of the response rate virtually impossible for each trial. 5-FU and MMC are two main drugs so far in single-agent chemotherapy, but streptozotocin, doxorubicin, ifosfamide, epirubicin and CDDP are also investigated. FAM and SMF are the representative regimen of combination chemotherapy, but recently FP or biochemical modulation have been under close scruting. For greater improvement of chemotherapy, a new drug or combined modality approach is awaited.

Antineoplastic Agents↗
PubMed1992

[The effects of potassium concentration in reperfusion solution upon myocardial protection].

The effects of potassium in reperfusion solution (RS) and the influence of sodium on this effect were studied. Experimental time course was as followed: 20 min working perfusion, 3 min cardioplegic infusion with St. Thomas Cardioplegic Solution followed by global ischemia for 33 or 35 min at 37.5 degrees C, 15 min early Langendorff reperfusion with several different potassium concentration modified with Krebs Henseleit Bicarbonate Buffer (KHBB) containing 145 mM and 110 mM sodium and 5 min late reperfusion with KHBB, followed by 20 min working perfusion. Potassium in RS possessed bell shaped dose response nature with optimal concentration of 10 mM in the condition of 145 mM sodium but 6 m in the condition of 110 mM in terms of percent recovery of aortic flow. Although higher potassium reperfusion produced less Creatine Kinase leakage.

Animals↗
PubMed1992

Age-dependent induction of thymic lymphomas by N-propyl-N-nitrosourea in the F344/DuCrj rat.

N-Propyl-N-nitrosourea (PNU) is one of the most potent thymic-lymphomagenic agents in rats. Our previous experiments strongly suggested that leukemogenic viruses were not the cause of thymic lymphomas in rats and that target cells of PNU exist in the thymus but not in the bone marrow. On the other hand, the role of retrovirus in lymphomagenesis is undeniable in mice. Therefore, chemically induced rat thymic lymphoma provides a good model to analyse lymphomagenesis without viral implications. In the present experiment 1, we investigated the relationship between the age of animal at commencement of PNU treatment and the incidence of thymic lymphomas. Incidences of thymic lymphomas were 100, 100, 80 and 18, and average latent periods were 15.1, 18.7, 25.4 and 27.3 weeks after the start of PNU-treatment, in 5-, 10-, 20- and 40-week-old groups, respectively. In experiment 2, rats were sacrificed postnatally at 5, 10, 20, 30 and 40 weeks each, and thymus weight, number of thymocytes in the thymus, frequency of mitosis, and percentage of OX-7 (Thy 1.1), OX-8 (CD8), or W3/25 (CD4) positive cells, were examined cytologically. Thymus weight, number of cells in the thymus and mitotic index were maximum at 10 weeks old, and thereafter decreased gradually. No marked changes were observed in the ratio of each cell-surface marker positive cell. These results indicate that induction of thymic lymphomas by PNU is very closely related with the total number of mitotic cells in the thymus. Thus, chemical induction of rat thymic lymphoma reflects an age-dependent function of the thymus.

Age Factors↗
PubMed1992

[A case of anomalous courses of the brachiocephalic artery, trachea, and esophagus].

A case was described in which the brachiocephalic artery ran transversely in front of the fourth tracheal ring. The abnormal course of this artery may present a possible hazard in the event of a tracheotomy. In this case the anomalous artery was accompanied by a shift of the trachea to the right and of the esophagus to the left. As a consequence, the left recurrent laryngeal nerve ascended in front of the esophagus. The anomalous nerve course may present the possibility of injury to the nerve in the event of a curative operation for esophageal cancer.

Brachiocephalic Veins↗
PubMed1992

[The effects of sodium concentration in reperfusion solution upon myocardial protection].

The effects of several sodium concentrations in reperfusion solution (RS) were studied. Experimental time course was as follows: 20 min working perfusion, 3 min cardioplegic infusion with St. Thomas Cardioplegic Solution followed by global ischemia for 33 min at 37.5 degrees C, 15 min early Langendorff reperfusion with various sodium concentrations modified with Krebs Henseleit Bicarbonate Buffer (KHBB) and 5 min late reperfusion with KHBB, followed by 20 min working perfusion. Percent recoveries of aortic flow and Creatine Kinase leakage showed that 110 mM sodium of RS possessed optimal protective properties with bell shaped dose response characteristics.

Animals↗
PubMed1992

[The effects of osmolarity in reperfusion solution upon myocardial protection].

The effects of several different osmolarity in reperfusion solution were studied. Experimental time course was as follows: 20 min working perfusion, 3 min cardioplegic infusion with St. Thomas Cardioplegic Solution (STS) followed by global ischemia for 33 min at 37.5 degrees C, 15 min early Langendorff reperfusion with different osmolarity by adding sucrose and 5 min late reperfusion with Krebs Henseleit bicarbonate buffer, followed by 20 min working perfusion. Percent recoveries of aortic flow showed that 290 mOsm/L in reperfusion solution possessed optimal protective properties with bell shaped dose response characteristics.

Animals↗
PubMed1991

Structure and developmental expression of troponin I isoforms. cDNA clone analysis of avian cardiac troponin I mRNA.

We isolated avian (chicken and quail) cardiac troponin I (TnIcardiac) cDNA clones for studies of Tn-Icardiac protein structure/evolution and developmental gene regulation. Comparison of the cDNA-predicted avian TnIcardiac amino acid sequences with known TnI sequences indicated 1) that the presence of an N-terminal extension sequence carrying a dual protein kinase A phosphorylation target site and an adjacent proline-rich segment is an ancient cardiac-specific feature of TnI which has been conserved since the bird/mammal divergence, 2) that features of the near-N-terminal troponin C (TnC)-binding site sequence suggest isoform-specific adaptation of TnI and TnC, and 3) that the avian TnIcardiac internal actin/TnC-binding, actomyosin-inhibitory, domain shows significant sequence divergence from mammalian TnIcardiac sequences, including the absence of a protein kinase C target site which is a cardiac-specific feature of TnI in mammals. Use of the cDNA clones to probe TnIcardiac mRNA expression during striated muscle development showed active expression in cardiac muscle from early developmental times (day 4 in ovo), but not in embryonic or adult skeletal muscle or in embryonic skeletal muscle cell cultures. Transcriptional run-on analysis showed that the heart-specific expression of TnIcardiac mRNA in embryonic striated muscle reflects transcriptional control of TnIcardiac gene expression. In many other contractile protein gene families, genes encoding cardiac isoforms are expressed early in skeletal muscle development and are later repressed. Thus, the restriction of active TnIcardiac gene expression to the cardiac muscle cell lineage is an unusual expression pattern for cardiac contractile protein genes and indicates that diverse gene regulatory mechanisms direct the differential expression of cardiac and skeletal muscle isoforms in different muscle gene families.

Amino Acid Sequence↗
PubMed1991

Changes in preference for receptor subtypes of configurational variants of a glutamate analog: conversion from the NMDA-type to the non-NMDA type.

The (2S,3R,4S) isomer of 2-(carboxycyclopropyl)glycines (CCG) (L-CCG-IV) is a potent NMDA-type agonist in the mammalian central nervous system. L-CCG-IV is a conformationally restricted glutamate analogue in which the cyclopropyl group fixes the glutamate chain, and closely mimics the folded conformation of L-glutamate. (6R)-Substituted L-CCG-IV, however, demonstrated pharmacological properties of non-NMDA type agonists in the newborn rat spinal motoneuron while (6S)-CCG derivatives showed similar properties to the parent compound, L-CCG-IV. In the dorsal root fiber of newborn rats, (6R)-methoxymethyl and benzyloxymethyl substituted L-CCG-IV caused kainate-like depolarization. The depolarizing potency of (6R)-benzyloxymethyl substituted L-CCG-IV was slightly lower than that of kainate, demonstrating a relatively high potency.

Amino Acids, Dicarboxylic↗
PubMed1991

Deletion of 17p and amplification of the int-2 gene in esophageal carcinomas.

We have analyzed allelic deletion at 23 loci on 18 different chromosomes in 35 esophageal squamous cell carcinoma tissues by using restriction fragment length polymorphism markers. Loss of heterozygosity was detected on chromosomes 2, 3, 6, 7, 11-14, 16-18, 21, and 22, while no loss was detected on chromosomes 1, 4, and 8-10. Only the loss of chromosome 17p was detected with high frequency (45%), and losses on other chromosomes had frequencies of less than 22%. These losses with low frequencies might be random losses caused by chromosomal rearrangement during the course of tumor development and progression. On the contrary, the loss of 17p might play an important role in the development of esophageal squamous cell carcinoma, such as inactivation of a tumor suppressor gene. Amplification of the int-2 gene was observed in 39% of the tumors. However, no significant relationship between int-2 amplification and the deletion of any chromosome was detected.

Aged↗
PubMed1991

Quantitation of urinary chlorobenzene metabolites by HPLC: concentrations of 4-chlorocatechol and chlorophenols in urine and of chlorobenzene in biological specimens of subjects exposed to chlorobenzene.

A simple method for the determination of 4-chlorocatechol (ClCh, 4-chloro-1,2-benzenediol) and chlorophenols (ClPh), metabolites of monochlorobenzene (ClBz), in urine by high performance liquid chromatography (HPLC) is described. Enzymatic hydrolysates of urine were applied to a stainless-steel column packed with octadecyl-silanized silica gel, and a mixed solution of 20 mM potassium phosphate monobasic: acetonitryl (75:25, v/v) was used as a mobile phase. The procedures for ether extraction and evaporation of extract could be omitted. The accuracy and precision of the present HPLC method were satisfactory. The excretion kinetics of ClCh and p-ClPh were investigated over 35 h after cessation of ClBz inhalation. Proportional relationships between concentrations of ClBz in air and of its metabolites in urine were observed. The slopes of regression lines predicting the levels of ClCh, p-ClPh and total ClPh in urine taken during the last 2 h of exposure to ClBz in air were 6.56, 1.13 and 2.83 mg/g creatinine for 1 ppm ClBz, respectively. ClBz in the blood and the end exhaled air of subjects at the end of exposure were identified by gas chromatography (GC) and mass spectrometry. A proportional relationship was observed between the concentration of ClBz in air and that in blood. The validity of the threshold limit value (TLV) for ClBz as evaluated from the subjective and objective symptoms is discussed.

Adult↗
PubMed1991

Evaluation of a new reflectance pulse oximeter for clinical applications.

The design of a noninvasive reflectance pulse oximeter that uses the same principle of transmittance pulse oximeter and analyses the oxygen saturation of arterial blood was described. Four sets of red and infra-red LEDs were used as light sources. The respective reflectance photoelectric outputs were used to make an internal calibration curve of the instrument relative to the arterial oxygen saturation values measured with a Co-Oximeter (OSM-3) in five healthy nonsmoking subjects during steady-state hypoxaemia. The accuracy of the present instrument was studied in six patients with respiratory failure. From 22 samples, a good correlation coefficient (0.98) with a standard deviation of 1.42 was obtained in the range between 73 and 100 per cent between the arterial oxygen saturation measured with the present instrument and that with the Co-Oximeter. The result strongly suggests the usefulness of this oximeter in monitoring patients with hypoxaemia.

Adult↗
PubMed1991

An early phase II study of 5-fluorouracil combined with cisplatinum as a second line chemotherapy against metastatic gastric cancer.

Twenty-two patients with measurable metastatic gastric cancer, refractory to prior chemotherapy, were treated with a combination chemotherapy of 5-fluorouracil (5FU) and cisdiamminedichroloplatinum (II) (CDDP). 5FU was continuously infused for five consecutive days at a dose of 800 mg/m2/day, and CDDP was given intravenously for five days at a dose of 20 mg/m2/day over 30 min every four weeks. All patients had received only one regimen of prior chemotherapy, and 10 of the 22 had been pretreated with combination of etoposide, doxorubicin and CDDP (EAP). It was possible to evaluate 20 of the 22 patients treated for response and toxicity. Nine of the 20 patients achieved a partial response, the response rate being 45% (23-67% with 95% confidence limits). The nine patients who responded included three who had been pretreated with EAP, indicating that 5FU + CDDP can be used as a second line chemotherapy against gastric cancer, even when the initial intensive chemotherapy, such as EAP, has failed to obtain or maintain a response. High grade toxicities (WHO grade 3 or 4) of leukocytopenia, thrombocytopenia and stomatitis were seen in 20, 25 and 40%, respectively. No treatment-related death was, however, observed. The above results suggest that 5FU + CDDP could be promising in a phase II trial with a large number of cases.

Adenocarcinoma↗
PubMed1991

Monitoring hepatic venous hemoglobin oxygen saturation in patients undergoing liver surgery.

Hepatic venous oxygen saturation (ShvO2) was continuously monitored in 33 consecutive patients undergoing hepatic lobectomy. Fiberoptic pulmonary artery catheters were inserted into the hepatic vein (HV) and in the pulmonary artery through the right internal jugular vein before anesthetic induction. The success rate and mean time for HV catheterization were 100% and 14 min, respectively. The only complication of the procedure was nonsustained atrial or ventricular arrhythmias. Eighteen patients showed decreases in ShvO2 to less than 30% at skin incision, at temporary cessation of hepatic inflow, and/or at surgical manipulation of the liver. Clinical HV catheterization was easy to accomplish and may be a valuable technique in studying the extent and significance of hepatic ischemia during liver surgery.

Aged↗
PubMed1991

Scanning electron microscopic observations of three-dimensional structure of the rat pancreatic duct.

To understand the fine, three-dimensional structure of the pancreatic duct, we made corrosion casts of rat pancreatic ducts and obtained biological specimens of rat pancreatic tissues for scanning electron microscopic observation. We observed the corrosion casts and the inner surfaces of the pancreatic duct specimens, using scanning electron microscopy. A comparative study between casts and specimens demonstrated the exactitude of our corrosion casts. These findings revealed the following facts: 1) The pancreatic ductal system had an almost tree-like shape, but parts of the intercalated ducts anastomosed with each other; 2) Intralobular ducts branched almost at a right angle from the interlobular ducts. Intercalated ducts, which branched off from the intralobular ducts, wound and forked into two branches, without any decrease in thickness. The intercellular secretory canaliculi extended from the central lumina, running straight through the center of the acini, close to the cell bases; 3) In pancreatic ducts, every lumen was covered with microvilli. The diameters of these microvilli were uniform (about 0.1 micron), but the heights were variable, even within a given pancreatic duct.

Animals↗